Endoscopes are elongate instruments navigable through natural body lumens of a patient for the purpose of remotely evaluating and treating a variety of ailments. Endoscopes have viewing capability provided by fiber optic elements that transmit images along their length to the medical care provider. Endoscopes may specifically configured in length, diameter, flexibility and lumen configuration to navigate specific treatment areas in the body. Such specifically configured endoscopes may be known as a laparoscope, duodenoscope, colonoscope, sigmoidoscope, bronchoscope and urethroscope among others. In combination with remote viewing capability, endoscopes are frequently configured to provide a working channel through which shaft mounted tools and medical instruments may be navigated and remotely operated. Additionally, the endoscope shaft itself may carry a medical instrument for remotely performing a procedure at an internal treatment site, while permitting direct visualization of the site through the endoscope.
The present invention addresses the problem of making an endoscopic accessory readily joinable to a range of endoscope sizes that are commercially available from a variety of manufacturers. Endoscopic accessories may include such instruments as forceps, band ligators or suturing devices, among others. The devices generally mount to at least a small portion of the outside surface of an endoscope shaft. A common mechanism for attachment of the accessory to the endoscope is by frictional engagement. The accessory is provided with a proximal portion having a circular or semicircular cross-section capable of fitting over the cylindrical shaft of the endoscope. The diameter defined by the proximal end of the accessory is sized to provide a frictional engagement with the endoscope shaft surface. An elastic gasket or ring may additionally be inserted between the endoscope shaft and the accessory to promote frictional engagement. However, because there is no standardized endoscope size and different endoscope manufacturers make endoscopes of different diameters, ensuring that the selected endoscope accessory will be sized appropriately to frictionally engage an endoscope can be problematic. This is especially so considering that the selected endoscope accessory may be manufactured by a different supplier than that of the endoscope. The present invention endeavors to provide a mounting adapter that will be usable with a variety of endoscopic accessories to provide a secure mounting to a variety of endoscope shaft sizes.
Another potential problem with current endoscopic accessory mounting techniques is insuring a proper support and alignment of the accessory in relation to the endoscope shaft. In particular, an endoscope accessory having a cylindrical receptacle that mounts along a length of the distal end of the endoscope shaft may not be adequately supported by a narrow circular area of frictional engagement at one end of the cylindrical receptacle. For example, if a cylindrical accessory is engaged with the endoscope shaft only by a single elastic ring at the proximal end of the device, the accessory may become misaligned at its distal end so that it is not concentric with the endoscope shaft. The accessory is then not aligned with the longitudinal axis of the endoscope, which can lead to mispositioning of the accessory relative to the intended treatment site. The present invention endeavors to provide an adapter that centers the accessory on the endoscope shaft maintaining it concentric along its length so that it is substantially aligned with the longitudinal axis of the endoscope.